Process for the preparing via the in situ reduction of their components and grinding oxide/metal composite materials

Abstract

A process for the preparation of composite materials consisting essentially of an oxide phase and a metal phase is effected by grinding a mixture of at least one oxide precursor of the metal phase of the composite with at least one reducing agent, the reducing agent being a precursor of the oxide phase. The grinding being performed in a high energy mechanical grinder for a sufficient length of time so that at least 80 percent of the oxide precursor is reduced to metal or to a metal alloy. The process is particularly valuable for the preparation of oxide/metal composite materials which have improved mechanical, electrical or radiation absorption properties.

We claim: 
     
       1. A process for the preparation of composite materials consisting essentially of an oxide phase and a metal phase, said process comprising the step of: grinding a mixture of at least one oxide precursor of said metal phase of said composite with at least one reducing agent, said reducing agent being a precursor of said oxide phase of said composite, to yield a mixture wherein the amount of said reducing agent is in the stoichiometric range of 90 percent to 110 percent of the amount necessary to reduce said oxide precursor to said metal phase,   in a high energy mechanical grinder for a sufficient length of time so that at least 80 percent of said oxide precursor is reduced to said metal phase or to a metal alloy phase, wherein no external heat is applied to said grinder during said grinding step.   
     
     
       2. The process of claim 1, wherein said oxide precursor of said metal phase is one chosen from the group consisting of the oxides of V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, Ag, W and mixtures thereof. 
     
     
       3. The process of claim 1, wherein no external heat is applied to said oxide precursor and said reducing agent before said grinding step. 
     
     
       4. The process of claim 1, wherein said grinding is performed in an inert gas atmosphere. 
     
     
       5. The process of claim 1, wherein said reducing agent is a metal selected from the group consisting of aluminum, titanium, yttrium, zirconium, magnesium, thorium and mixtures thereof. 
     
     
       6. The process of claim 1, wherein said oxide precursor and said reducing agent are heated to a temperature of less than 200° C. before being placed into said grinder. 
     
     
       7. The process of claim 1, wherein said reducing agent is aluminum. 
     
     
       8. The process of claim 1, wherein said oxide precursor is a mixture of oxides of Fe and Cr, and said reducing agent is Al. 
     
     
       9. The process of claim 1, wherein said oxide precursor is a mixture of oxides of Fe, Cr and Ni, and said reducing agent is Al. 
     
     
       10. The process of claim 1, wherein said metal is in the form of an alloy containing at least 90% by weight of said metal.